1. Field of the Invention
Disclosed herein is a multi-joint link mechanism such as a robot arm. More particularly, disclosed herein are a weight compensation mechanism for absorbing the influence of weight such as gravitation and a robot arm using the weight compensation mechanism.
2. Description of the Related Art
Recently, various robots have been developed, which facilitates life environment of human beings or assists work in industrial sites. Particularly, a large number of robots have been developed, which are used in various industrial fields including painting, welding and the like. Since such industrial multi-joint robot arms necessarily transfer and support high-weight objects for work, it is very important for the robots to output high torque.
Such a multi-joint robot arm receives load torque caused by its own weight or the weight of an object for work, and such load torque has direct influence on the design of the capacity of a driver such as a drive motor. Particularly, the relative importance of the torque component generated by the weight of the robot arm is very high in the weight applied to the drive motor.
When the capacity of a driver is determined in a related art robot arm, the gravitational torque generated by the weight of the robot arm is necessarily considered in addition to the torque generated by an object for work. Therefore, the capacity of a power source for driving the robot arm is necessarily increased. Also, a simple idea about the concept of theoretically compensating the gravitation generated by the weight of a robot arm or the like was conventionally proposed, but mechanisms to which the idea is practically applied have not been developed.